I just want to double check this condition problem with a book I received. It is a paperback and the cover is coming unglued from the spine. It is about 1/4 to 1/2" completely off the glue, which means it shouldn't have been posted, right? So it is not in a fit condition to be reposted when I finish reading it?

You can also sometimes melt the glue that is already there, with a warm iron. Covervthe paper with a layer of paper towel, or washcloth, and hold the iron against that for 30seconds or so until the glue melts.